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Bioremediation of benzene, ethylbenzene, and xylenes in groundwater under iron‐amended, sulfate‐reducing conditions
Author(s) -
Jin Song,
Fallgren Paul H.,
Bilgin A. Azra,
Morris Jeffrey M.,
Barnes Paul W.
Publication year - 2007
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1897/06-234r.1
Subject(s) - ethylbenzene , environmental chemistry , microcosm , bioremediation , chemistry , biostimulation , benzene , groundwater , biodegradation , toluene , xylene , population , microbial consortium , sulfide , amendment , contamination , microorganism , bacteria , geology , ecology , organic chemistry , biology , paleontology , demography , geotechnical engineering , sociology , political science , law
—Elevated concentrations of sulfide in groundwater (∼63 mg S 2− /L in water and 500 mg dissolved H 2 S/L dissipating from the wellhead) at a field site near South Lovedale (OK, USA) were inhibiting the activity of sulfate‐reducing bacteria (SRB) that are known to degrade contaminants, including benzene, toluene, ethylbenzene, and xylenes. Elevated concentrations of these contaminants, except for toluene, also were present in this groundwater. Microcosms were established in the laboratory using groundwater and sediment collected from the field site and amended with various nutrient, substrate, and inhibitor treatments. All microcosms initially were amended with FeCl 2 to induce FeS precipitation and, thereby, to reduce aqueous sulfide concentrations. Complete removal of benzene, ethylbenzene, and m+p ‐xylenes (BEX; o ‐xylene not detected) was observed within 39 d in treatments with various combinations of nutrient and substrate amendments, including treatments with no amendments (other than FeCl 2 ). This indicates that the elevated concentration of sulfide is the only limiting factor to BEX biodegradation at this site under anaerobic conditions and that treating the groundwater with FeCl 2 may be a simple remedy to both facilitate and enhance BEX degradation by the indigenous SRB population.